[net-next-2.6.git] / security / selinux / netif.c

/*
 * Network interface table.
 *
 * Network interfaces (devices) do not have a security field, so we
 * maintain a table associating each interface with a SID.
 *
 * Author: James Morris <jmorris@redhat.com>
 *
 * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
 * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
 *		      Paul Moore <paul.moore@hp.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2,
 * as published by the Free Software Foundation.
 */
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/rcupdate.h>
#include <net/net_namespace.h>

#include "security.h"
#include "objsec.h"
#include "netif.h"

#define SEL_NETIF_HASH_SIZE	64
#define SEL_NETIF_HASH_MAX	1024

struct sel_netif {
	struct list_head list;
	struct netif_security_struct nsec;
	struct rcu_head rcu_head;
};

static u32 sel_netif_total;
static LIST_HEAD(sel_netif_list);
static DEFINE_SPINLOCK(sel_netif_lock);
static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];

/**
 * sel_netif_hashfn - Hashing function for the interface table
 * @ifindex: the network interface
 *
 * Description:
 * This is the hashing function for the network interface table, it returns the
 * bucket number for the given interface.
 *
 */
static inline u32 sel_netif_hashfn(int ifindex)
{
	return (ifindex & (SEL_NETIF_HASH_SIZE - 1));
}

/**
 * sel_netif_find - Search for an interface record
 * @ifindex: the network interface
 *
 * Description:
 * Search the network interface table and return the record matching @ifindex.
 * If an entry can not be found in the table return NULL.
 *
 */
static inline struct sel_netif *sel_netif_find(int ifindex)
{
	int idx = sel_netif_hashfn(ifindex);
	struct sel_netif *netif;

	list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list)
		/* all of the devices should normally fit in the hash, so we
		 * optimize for that case */
		if (likely(netif->nsec.ifindex == ifindex))
			return netif;

	return NULL;
}

/**
 * sel_netif_insert - Insert a new interface into the table
 * @netif: the new interface record
 *
 * Description:
 * Add a new interface record to the network interface hash table.  Returns
 * zero on success, negative values on failure.
 *
 */
static int sel_netif_insert(struct sel_netif *netif)
{
	int idx;

	if (sel_netif_total >= SEL_NETIF_HASH_MAX)
		return -ENOSPC;

	idx = sel_netif_hashfn(netif->nsec.ifindex);
	list_add_rcu(&netif->list, &sel_netif_hash[idx]);
	sel_netif_total++;

	return 0;
}

/**
 * sel_netif_free - Frees an interface entry
 * @p: the entry's RCU field
 *
 * Description:
 * This function is designed to be used as a callback to the call_rcu()
 * function so that memory allocated to a hash table interface entry can be
 * released safely.
 *
 */
static void sel_netif_free(struct rcu_head *p)
{
	struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
	kfree(netif);
}

/**
 * sel_netif_destroy - Remove an interface record from the table
 * @netif: the existing interface record
 *
 * Description:
 * Remove an existing interface record from the network interface table.
 *
 */
static void sel_netif_destroy(struct sel_netif *netif)
{
	list_del_rcu(&netif->list);
	sel_netif_total--;
	call_rcu(&netif->rcu_head, sel_netif_free);
}

/**
 * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
 * @ifindex: the network interface
 * @sid: interface SID
 *
 * Description:
 * This function determines the SID of a network interface by quering the
 * security policy.  The result is added to the network interface table to
 * speedup future queries.  Returns zero on success, negative values on
 * failure.
 *
 */
static int sel_netif_sid_slow(int ifindex, u32 *sid)
{
	int ret;
	struct sel_netif *netif;
	struct sel_netif *new = NULL;
	struct net_device *dev;

	/* NOTE: we always use init's network namespace since we don't
	 * currently support containers */

	dev = dev_get_by_index(&init_net, ifindex);
	if (unlikely(dev == NULL)) {
		printk(KERN_WARNING
		       "SELinux: failure in sel_netif_sid_slow(),"
		       " invalid network interface (%d)\n", ifindex);
		return -ENOENT;
	}

	spin_lock_bh(&sel_netif_lock);
	netif = sel_netif_find(ifindex);
	if (netif != NULL) {
		*sid = netif->nsec.sid;
		ret = 0;
		goto out;
	}
	new = kzalloc(sizeof(*new), GFP_ATOMIC);
	if (new == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	ret = security_netif_sid(dev->name, &new->nsec.sid);
	if (ret != 0)
		goto out;
	new->nsec.ifindex = ifindex;
	ret = sel_netif_insert(new);
	if (ret != 0)
		goto out;
	*sid = new->nsec.sid;

out:
	spin_unlock_bh(&sel_netif_lock);
	dev_put(dev);
	if (unlikely(ret)) {
		printk(KERN_WARNING
		       "SELinux: failure in sel_netif_sid_slow(),"
		       " unable to determine network interface label (%d)\n",
		       ifindex);
		kfree(new);
	}
	return ret;
}

/**
 * sel_netif_sid - Lookup the SID of a network interface
 * @ifindex: the network interface
 * @sid: interface SID
 *
 * Description:
 * This function determines the SID of a network interface using the fastest
 * method possible.  First the interface table is queried, but if an entry
 * can't be found then the policy is queried and the result is added to the
 * table to speedup future queries.  Returns zero on success, negative values
 * on failure.
 *
 */
int sel_netif_sid(int ifindex, u32 *sid)
{
	struct sel_netif *netif;

	rcu_read_lock();
	netif = sel_netif_find(ifindex);
	if (likely(netif != NULL)) {
		*sid = netif->nsec.sid;
		rcu_read_unlock();
		return 0;
	}
	rcu_read_unlock();

	return sel_netif_sid_slow(ifindex, sid);
}

/**
 * sel_netif_kill - Remove an entry from the network interface table
 * @ifindex: the network interface
 *
 * Description:
 * This function removes the entry matching @ifindex from the network interface
 * table if it exists.
 *
 */
static void sel_netif_kill(int ifindex)
{
	struct sel_netif *netif;

	rcu_read_lock();
	spin_lock_bh(&sel_netif_lock);
	netif = sel_netif_find(ifindex);
	if (netif)
		sel_netif_destroy(netif);
	spin_unlock_bh(&sel_netif_lock);
	rcu_read_unlock();
}

/**
 * sel_netif_flush - Flush the entire network interface table
 *
 * Description:
 * Remove all entries from the network interface table.
 *
 */
static void sel_netif_flush(void)
{
	int idx;
	struct sel_netif *netif;

	spin_lock_bh(&sel_netif_lock);
	for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
		list_for_each_entry(netif, &sel_netif_hash[idx], list)
			sel_netif_destroy(netif);
	spin_unlock_bh(&sel_netif_lock);
}

static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
				  u16 class, u32 perms, u32 *retained)
{
	if (event == AVC_CALLBACK_RESET) {
		sel_netif_flush();
		synchronize_net();
	}
	return 0;
}

static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
					     unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;

	if (dev_net(dev) != &init_net)
		return NOTIFY_DONE;

	if (event == NETDEV_DOWN)
		sel_netif_kill(dev->ifindex);

	return NOTIFY_DONE;
}

static struct notifier_block sel_netif_netdev_notifier = {
	.notifier_call = sel_netif_netdev_notifier_handler,
};

static __init int sel_netif_init(void)
{
	int i, err;

	if (!selinux_enabled)
		return 0;

	for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
		INIT_LIST_HEAD(&sel_netif_hash[i]);

	register_netdevice_notifier(&sel_netif_netdev_notifier);

	err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET,
			       SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
	if (err)
		panic("avc_add_callback() failed, error %d\n", err);

	return err;
}

__initcall(sel_netif_init);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Network interface table.
	3	*
	4	* Network interfaces (devices) do not have a security field, so we
	5	* maintain a table associating each interface with a SID.
	6	*
	7	* Author: James Morris <jmorris@redhat.com>
	8	*
	9	* Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
e8bfdb9d	10	* Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
338366cb	11	* Paul Moore <paul.moore@hp.com>
1da177e4 LT	12	*
	13	* This program is free software; you can redistribute it and/or modify
	14	* it under the terms of the GNU General Public License version 2,
	15	* as published by the Free Software Foundation.
	16	*/
	17	#include <linux/init.h>
	18	#include <linux/types.h>
5a0e3ad6	19	#include <linux/slab.h>
1da177e4 LT	20	#include <linux/stddef.h>
	21	#include <linux/kernel.h>
	22	#include <linux/list.h>
	23	#include <linux/notifier.h>
	24	#include <linux/netdevice.h>
	25	#include <linux/rcupdate.h>
e9dc8653	26	#include <net/net_namespace.h>
1da177e4 LT	27
	28	#include "security.h"
	29	#include "objsec.h"
	30	#include "netif.h"
	31
	32	#define SEL_NETIF_HASH_SIZE 64
	33	#define SEL_NETIF_HASH_MAX 1024
	34
338366cb	35	struct sel_netif {
1da177e4 LT	36	struct list_head list;
	37	struct netif_security_struct nsec;
	38	struct rcu_head rcu_head;
	39	};
	40
	41	static u32 sel_netif_total;
	42	static LIST_HEAD(sel_netif_list);
	43	static DEFINE_SPINLOCK(sel_netif_lock);
	44	static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
	45
e8bfdb9d PM	46	/**
	47	* sel_netif_hashfn - Hashing function for the interface table
	48	* @ifindex: the network interface
	49	*
	50	* Description:
	51	* This is the hashing function for the network interface table, it returns the
	52	* bucket number for the given interface.
	53	*
	54	*/
	55	static inline u32 sel_netif_hashfn(int ifindex)
1da177e4	56	{
e8bfdb9d	57	return (ifindex & (SEL_NETIF_HASH_SIZE - 1));
1da177e4 LT	58	}
1da177e4 LT	59
e8bfdb9d PM	60	/**
	61	* sel_netif_find - Search for an interface record
	62	* @ifindex: the network interface
	63	*
	64	* Description:
	65	* Search the network interface table and return the record matching @ifindex.
	66	* If an entry can not be found in the table return NULL.
	67	*
1da177e4	68	*/
e8bfdb9d	69	static inline struct sel_netif *sel_netif_find(int ifindex)
1da177e4	70	{
e8bfdb9d PM	71	int idx = sel_netif_hashfn(ifindex);
e8bfdb9d PM	72	struct sel_netif *netif;
1da177e4	73
e8bfdb9d PM	74	list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list)
	75	/* all of the devices should normally fit in the hash, so we
	76	* optimize for that case */
	77	if (likely(netif->nsec.ifindex == ifindex))
1da177e4	78	return netif;
e8bfdb9d	79
1da177e4 LT	80	return NULL;
	81	}
	82
e8bfdb9d PM	83	/**
	84	* sel_netif_insert - Insert a new interface into the table
	85	* @netif: the new interface record
	86	*
	87	* Description:
	88	* Add a new interface record to the network interface hash table. Returns
	89	* zero on success, negative values on failure.
	90	*
	91	*/
1da177e4 LT	92	static int sel_netif_insert(struct sel_netif *netif)
1da177e4 LT	93	{
e8bfdb9d	94	int idx;
338366cb	95
e8bfdb9d PM	96	if (sel_netif_total >= SEL_NETIF_HASH_MAX)
e8bfdb9d PM	97	return -ENOSPC;
338366cb	98
e8bfdb9d	99	idx = sel_netif_hashfn(netif->nsec.ifindex);
1da177e4 LT	100	list_add_rcu(&netif->list, &sel_netif_hash[idx]);
1da177e4 LT	101	sel_netif_total++;
e8bfdb9d PM	102
e8bfdb9d PM	103	return 0;
1da177e4 LT	104	}
1da177e4 LT	105
e8bfdb9d PM	106	/**
	107	* sel_netif_free - Frees an interface entry
	108	* @p: the entry's RCU field
	109	*
	110	* Description:
	111	* This function is designed to be used as a callback to the call_rcu()
	112	* function so that memory allocated to a hash table interface entry can be
	113	* released safely.
	114	*
	115	*/
1da177e4 LT	116	static void sel_netif_free(struct rcu_head *p)
	117	{
	118	struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
1da177e4 LT	119	kfree(netif);
	120	}
	121
e8bfdb9d PM	122	/**
	123	* sel_netif_destroy - Remove an interface record from the table
	124	* @netif: the existing interface record
	125	*
	126	* Description:
	127	* Remove an existing interface record from the network interface table.
	128	*
	129	*/
1da177e4 LT	130	static void sel_netif_destroy(struct sel_netif *netif)
1da177e4 LT	131	{
1da177e4 LT	132	list_del_rcu(&netif->list);
	133	sel_netif_total--;
	134	call_rcu(&netif->rcu_head, sel_netif_free);
	135	}
	136
e8bfdb9d PM	137	/**
	138	* sel_netif_sid_slow - Lookup the SID of a network interface using the policy
	139	* @ifindex: the network interface
	140	* @sid: interface SID
	141	*
	142	* Description:
	143	* This function determines the SID of a network interface by quering the
	144	* security policy. The result is added to the network interface table to
	145	* speedup future queries. Returns zero on success, negative values on
	146	* failure.
	147	*
	148	*/
	149	static int sel_netif_sid_slow(int ifindex, u32 *sid)
1da177e4 LT	150	{
1da177e4 LT	151	int ret;
e8bfdb9d PM	152	struct sel_netif *netif;
	153	struct sel_netif *new = NULL;
	154	struct net_device *dev;
1da177e4	155
e8bfdb9d PM	156	/* NOTE: we always use init's network namespace since we don't
e8bfdb9d PM	157	* currently support containers */
1da177e4	158
e8bfdb9d	159	dev = dev_get_by_index(&init_net, ifindex);
71f1cb05 PM	160	if (unlikely(dev == NULL)) {
	161	printk(KERN_WARNING
	162	"SELinux: failure in sel_netif_sid_slow(),"
	163	" invalid network interface (%d)\n", ifindex);
e8bfdb9d	164	return -ENOENT;
71f1cb05	165	}
1da177e4	166
1da177e4	167	spin_lock_bh(&sel_netif_lock);
e8bfdb9d PM	168	netif = sel_netif_find(ifindex);
	169	if (netif != NULL) {
	170	*sid = netif->nsec.sid;
	171	ret = 0;
1da177e4 LT	172	goto out;
1da177e4 LT	173	}
e8bfdb9d PM	174	new = kzalloc(sizeof(*new), GFP_ATOMIC);
	175	if (new == NULL) {
	176	ret = -ENOMEM;
1da177e4 LT	177	goto out;
1da177e4 LT	178	}
e8bfdb9d PM	179	ret = security_netif_sid(dev->name, &new->nsec.sid);
	180	if (ret != 0)
	181	goto out;
	182	new->nsec.ifindex = ifindex;
	183	ret = sel_netif_insert(new);
	184	if (ret != 0)
	185	goto out;
	186	*sid = new->nsec.sid;
1da177e4	187
1da177e4	188	out:
e8bfdb9d PM	189	spin_unlock_bh(&sel_netif_lock);
e8bfdb9d PM	190	dev_put(dev);
71f1cb05 PM	191	if (unlikely(ret)) {
	192	printk(KERN_WARNING
	193	"SELinux: failure in sel_netif_sid_slow(),"
	194	" unable to determine network interface label (%d)\n",
	195	ifindex);
e8bfdb9d	196	kfree(new);
71f1cb05	197	}
1da177e4 LT	198	return ret;
	199	}
	200
e8bfdb9d PM	201	/**
	202	* sel_netif_sid - Lookup the SID of a network interface
	203	* @ifindex: the network interface
	204	* @sid: interface SID
	205	*
	206	* Description:
	207	* This function determines the SID of a network interface using the fastest
	208	* method possible. First the interface table is queried, but if an entry
	209	* can't be found then the policy is queried and the result is added to the
	210	* table to speedup future queries. Returns zero on success, negative values
	211	* on failure.
	212	*
	213	*/
	214	int sel_netif_sid(int ifindex, u32 *sid)
1da177e4	215	{
1da177e4 LT	216	struct sel_netif *netif;
	217
	218	rcu_read_lock();
e8bfdb9d PM	219	netif = sel_netif_find(ifindex);
	220	if (likely(netif != NULL)) {
	221	*sid = netif->nsec.sid;
1da177e4	222	rcu_read_unlock();
e8bfdb9d	223	return 0;
1da177e4	224	}
1da177e4	225	rcu_read_unlock();
e8bfdb9d PM	226
e8bfdb9d PM	227	return sel_netif_sid_slow(ifindex, sid);
1da177e4 LT	228	}
1da177e4 LT	229
e8bfdb9d PM	230	/**
	231	* sel_netif_kill - Remove an entry from the network interface table
	232	* @ifindex: the network interface
	233	*
	234	* Description:
	235	* This function removes the entry matching @ifindex from the network interface
	236	* table if it exists.
	237	*
	238	*/
	239	static void sel_netif_kill(int ifindex)
1da177e4 LT	240	{
	241	struct sel_netif *netif;
	242
61844250	243	rcu_read_lock();
1da177e4	244	spin_lock_bh(&sel_netif_lock);
e8bfdb9d	245	netif = sel_netif_find(ifindex);
1da177e4 LT	246	if (netif)
	247	sel_netif_destroy(netif);
	248	spin_unlock_bh(&sel_netif_lock);
61844250	249	rcu_read_unlock();
1da177e4 LT	250	}
1da177e4 LT	251
e8bfdb9d PM	252	/**
	253	* sel_netif_flush - Flush the entire network interface table
	254	*
	255	* Description:
	256	* Remove all entries from the network interface table.
	257	*
	258	*/
1da177e4 LT	259	static void sel_netif_flush(void)
	260	{
	261	int idx;
e8bfdb9d	262	struct sel_netif *netif;
1da177e4 LT	263
1da177e4 LT	264	spin_lock_bh(&sel_netif_lock);
e8bfdb9d	265	for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
1da177e4 LT	266	list_for_each_entry(netif, &sel_netif_hash[idx], list)
1da177e4 LT	267	sel_netif_destroy(netif);
1da177e4 LT	268	spin_unlock_bh(&sel_netif_lock);
	269	}
	270
	271	static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
338366cb	272	u16 class, u32 perms, u32 *retained)
1da177e4 LT	273	{
	274	if (event == AVC_CALLBACK_RESET) {
	275	sel_netif_flush();
	276	synchronize_net();
	277	}
	278	return 0;
	279	}
	280
	281	static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
338366cb	282	unsigned long event, void *ptr)
1da177e4 LT	283	{
	284	struct net_device *dev = ptr;
	285
c346dca1	286	if (dev_net(dev) != &init_net)
e9dc8653 EB	287	return NOTIFY_DONE;
e9dc8653 EB	288
1da177e4	289	if (event == NETDEV_DOWN)
e8bfdb9d	290	sel_netif_kill(dev->ifindex);
1da177e4 LT	291
	292	return NOTIFY_DONE;
	293	}
	294
	295	static struct notifier_block sel_netif_netdev_notifier = {
	296	.notifier_call = sel_netif_netdev_notifier_handler,
	297	};
	298
	299	static __init int sel_netif_init(void)
	300	{
e8bfdb9d	301	int i, err;
338366cb	302
1da177e4	303	if (!selinux_enabled)
e8bfdb9d	304	return 0;
1da177e4 LT	305
	306	for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
	307	INIT_LIST_HEAD(&sel_netif_hash[i]);
	308
	309	register_netdevice_notifier(&sel_netif_netdev_notifier);
338366cb	310
1da177e4	311	err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET,
338366cb	312	SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
1da177e4 LT	313	if (err)
	314	panic("avc_add_callback() failed, error %d\n", err);
	315
1da177e4 LT	316	return err;
	317	}
	318
	319	__initcall(sel_netif_init);
	320